High intensity lights can be used to mark a structure over 500 feet in height that may be a hazard to aircraft navigation. Current high intensity lights use Xenon bulbs and do not offer the reliability and extended life cycle of newer designs.
In addition, the design of the Xenon based high intensity lights does not provide consistent light intensity horizontally throughout a 360 degree coverage. For example, the Xenon based high intensity lights are typically enclosed in a single module. The single module is typically a square or rectangular box enclosure with a window on one side where most of the light is emitted directly forward. The single module may not emit sufficient light at wide angles in the horizontal axis and, therefore, may not provide sufficient light output at all angles. Multiple Xenon based high intensity lights are used together on a level of the tower; however, there may be gaps where insufficient light is emitted and, therefore, the lights may not be seen clearly by pilots.
Xenon bulbs also tend to have a relatively short life expectancy compared to newer light technologies. Due to the remote locations of many towers and the height of the towers, replacing the Xenon bulbs frequently can lead to high maintenance costs and replacement costs.